Abrasive and Method of Fabricating Same

ABSTRACT

The invention relates to an abrasive wherein abrasive grains are embedded in a matrix comprising a non-cellular, particularly non-foamed thermosetting binder for the abrasive grains, and wherein a contact surface covered by abrasive grains is configured for abrasion of a workpiece. In accordance with the invention the matrix is elastically compliant to such an extent that the abrasive grains covering the contact surface are impressed into the matrix during abrasion. The abrasive grains are dispersed in the matrix such that the consumption of the matrix perpendicular to the contact surface covered originally with abrasive grains releases a further contact surface covered with abrasive grains. The abrasive grains are dispersed in the matrix such that they comply with the return force of the matrix both perpendicular and parallel to the corresponding contact surface of the abrasive. The matrix is bonded to a flexible backing. Bonding the matrix to its backing is achieved directly via the binder contained in the matrix.

The invention generally relates to an abrasive wherein abrasive grains are embedded in a matrix of a binder and wherein a contact surface covered by abrasive grains is configured for abrasion of a workpiece.

Ever since the start in the development of such abrasives it is known to fabricate their abrasive composites in an homogenous structure. For this purpose originally, use was made of non-elastic binders, but elastically compliant binders have since been employed for decades. One example of such an abrasive composite using non-elastic binders is a grindstone. Examples of abrasive composites employing elastically compliant binders are compact composites e.g. in the form of a cube or also other abrasive compacts formed e.g. as an abrasive wheel. Known in this respect are both cellular and non-cellular embodiments. These known abrasive compacts were and still are cast as a whole as practiced by the applicant with a more than 40 year proven record of success.

These known abrasives employing elastically compliant binders for the abrasive grains have hitherto been regularly fabricated without the substance integrated in the abrasive because of their configuration as abrasive compacts. By contrast, with abrasives having a non-elastic binder, “backed abrasives” termed as such in the branch are in a class of their own since decades.

The invention relates furthermore specially to abrasives having a non-cellular, particularly non-foamed binder in said contrast to the cellular, particularly foamed binder.

With reference to the German Plastics Handbook, “Saechtling Kunststoff Taschenbuch, 28^(th) Edition, by Karl Oberbach, published by Verlag Hansa, see page 555, FIG. 4.18” it is clear that a distinction is made generally between foamed materials and non-cellular binders in any case where PUR (polyurethane) is concerned, but also as regards all other foaming binders.

In this case the non-cellular PUR types particularly substantial to the invention belong to the group:

solid polyurethanes

cast and spray elastomers

thermoplastic elastomers

rubber

The elastically compliant compacts cited initially as prior art and “solid” composites in the cited grouping respectively are special cast elastomers, the abrasives in accordance with the invention also using particularly cast elastomers.

When the binders are fabricated foamed a distinction is made between materials foamed physically and mechanically by the application of air and materials foamed chemically by the application of blowing agents.

Abrasives having a non-cellular binder, to which the invention relates, are characterized by being targeted foamed neither physically nor chemically by the corresponding concrete handling of the process. The target instead is to avoid expansion within the scope of being maximum possible, although in practice remnant cellular formations can never be totally avoided. This is why—at least in describing the abrasive product as fabricated concretely designed for the market—it appears best to make reference to the real and theoretical densities as compared to actual practice.

For foaming binders this comparison is best illustrated by way of PUR, as an example. As it reads from the cited German Plastics Handbook “Saechtling Kunststoff Taschenbuch, 28^(th) Edition, by Karl Oberbach, published by Verlag Hansa, see page 554 et seq” a distinction is made between molded foams 30-300 kg/m³), rigid foams 30-90 kg/m³) and open-celled foams 20-40 kg/m³).

In accordance with the invention the PUR is employed, particularly with a density of no less than 800 kg/m³ which adequately describes the minimum porosity.

Backed binders in which the abrasive composite features a cellular and particularly foamed binder are already known for example from German patents DE 31 14 001 A1 and DE 19 07 983 A1.

The invention relates in conclusion particularly to the abrasives, the composite of which comprises a thermosetting binder of the abrasive grains. Here the invention recourses to the thermosetting plastics, such as for example of polyurethane, known as such as binders for abrasive grains of composites, although rubber may also be used in the scope of the invention as the binder for the abrasive grains.

One example of a thermoplastic binder for the abrasive grains in the form of a plasticized colloxyline reads from the German patent DD 106 585 A which different to the thermosetting plastics employed in the scope of the invention additionally requires the use of a plasticizer in roughly equal proportion 1:1 or 0.8:1.). Also required to prevent loading of the abrasive is a proportion of at least 60% by weight of the abrasive powder in the abrasive composite, a corresponding proportion of abrasive powder exceeding 80% being incidentally viewed as being detrimental for bonding the abrasive composite. This known abrasive composite is specially devised for configuring the abrasive composite as an extremely thin layer of abrasive in the range of 10 μm to maximum 40 μm thick as measured perpendicular to the backing.

Just for the sake of completeness reference is further made to a more exotic known abrasive, the binder of which for the abrasive grains is kneadable is thus alleging to adapt to the profile of a workpiece surface for abrasion (German patent DD 255 903 A1).

In the course of the technical development of the abrasives as presently involved the working speeds, e.g. in rotating or oscillating operation at the side of the abrasive tools or machines are becoming faster all the time, having resulted in since decades homogenous abrasives having elastically compliant binders becoming incapable of standing up to the resulting forces of acceleration and traction including centrifugal forces which, without special measures culminated in the matrix of the abrasive formed by the elastically compliant binder being prematurely ruined. One of these special measures used in conjunction with abrasive wheels involves dimensioning the abrasive coating of a solid core of the abrasive wheel forming the abrasive thinner and thinner, resulting in the useful life being relatively short. For endless abrasive belts it was also considered even almost half a century ago to coat an endless belt serving as the backing with strip-shaped abrasive composites, the matrix of which containing the abrasive grains is formed in each case by a compliant foam of polyurethane, whereby these abrasive grains were secured to the endless belt by means of a separate adhesive (see British patent GB B 821929, particularly page 2, lines 3 to 7). However, the gist of this invention necessitates an unreasonably complicated method in series production because of having to blank the abrasive composites and the separate bonding involved, this being the reason why this failed to find acceptance in practice.

For conventional erosive abrasion it has always been usual to bond the abrasive grains—the grain size of which is selected in accordance with the desired result—directly to a backing by means of a non-elastic binder, such as initially hide glue and now man-made resin. This backing absorbs the traction and centrifugal forces resulting in the machine. In this conventional case the abrasive grains are attached to the backing in just a single layer and jut from the surface in abrasive contact with the workpiece by abrasive protuberances. As soon as these protuberances have become worn down in abrasion, resulted in the binder coming into friction contact with the workpiece, the effectiveness in abrasion is significantly diminished and the nuisance of the binder loading the abraded surface of the workpiece occurs.

With an abrasive whose abrasive grains are homogenously arranged in a matrix of a radiation-cured non-elastic binder on a backing bonded via the binder, the matrix is divided into a plurality of matrix bodies dispersed mutually interspaced featuring in the direction the free contact surface with the workpiece with the workpiece to the backing an increasing cross-section parallel to the backing (German patent T2 692 10 221).

In other words, in erosive abrasion abrasive portions of abrasive grains protrude from the contact surface, the finish of the abraded surface being all the better the smaller the size of the abrasive grains. In this respect a distinction is needed as to finishing comparable to honing or lapping no longer involving substantially erosive abrasion but a reduction in the peak-to-valley height of the surface.

For use in modern abrasive machines it is now usual to provide abrasive non-wovens as the finishing abrasive. As it reads from German patent DE-T2 69609709 (particularly claim 4) a plurality of abrasive particles is bonded to an open loose fabric of organic fibers via a binder system. Finishing done therewith resulted in scabs in the surface being machined being bent out of the way or broken. Imperfections in the finished surface of the workpiece, such as scratches and scrapes are merely glossed over and not really eliminated

The invention is based on the object of providing an abrasive of the kind as it reads from the preamble of claim 1 which is suitable as an article for rational mass production for use as a finishing tool on modern abrasive machines in combining a long useful life with high consistency in finishing quality.

This object is achieved by an abrasive having the features of claim 1.

In the abrasive in accordance with the invention when new, a contact surface covered with abrasive grains is provided which as may be necessary needs to be exposed in the last phase of the production process by releasing a covering skin of the matrix binders resulted in portions of the abrasive grains protruding from the original first contact surface with the workpiece. When implementing finishing these protruding portions of the abrasive grains are impressed fully or near fully into the matrix in thus substantially eliminating an erosive abrasive action with the workpiece. Loading of the abraded surface of the workpiece is avoided or at least minimized in that during wear down of the abrasive grain covering of the matrix the previously surrounding resident binder does not come into loading contact with the abraded surface of the workpiece, it instead abrading like a rubber eraser. In this arrangement the abrasive grains are not worn down as such, but drop off bit by bit from the current contact surface. This loss of abrasive grains is regenerated continuously from the depth of the matrix so that during finishing, despite consumption of the matrix the finishing quality remains consistent. Indeed, this applies even up to total consumption of the matrix in its connection to the backing. In this arrangement the backing ensures a consistent working quality no matter to what degree the matrix is consumed even with high working parameters such as rotative speed, belt speed or ratings of an oscillation, whilst achieving rational and cost-effective fabrication of the abrasive in accordance with the invention in just a few working steps.

Particularly also to be emphasized is the finish achievable with the abrasive in accordance with the invention in conjunction with modern finishing machines as an improvement over what was possible hitherto. Thus the finish in accordance with the invention achievable with abrasive non-wovens is associated with a further additional minimally erosive effect of the abrasive grains as compared to the abrasive non-wovens whereby in accordance with the invention imperfection in the abrasive surface can now be not only concealed but abraded away or at least corrected. This now surprisingly makes it possible to subsequently chrome workpieces suitable therefor without further finishing being needed.

The abrasion is substantially determined by the selection of the binder, any fillers as may be employed and the type of grain of the abrasive grains. For machining the various materials, such as e.g. brass, aluminum or stainless steel the birder can be tailored thereto. The abrasive in accordance with the invention is particularly effective in finishing relatively rough workpiece surfaces. These can now be finished to extremely fine surfaces with no imperfections even when the abrasive grains are relatively coarse in the abrasive in accordance with the invention.

All this is achieved in a departure from the current development tendency by making a novel recourse to elastically compliant binders in the matrix after decades of being ignored.

Claims 2 to 43 relate to advantageous further embodiments of the abrasive in accordance with the invention and claims 44 to 49 relate to a preferred device for fabricating the abrasive in accordance with the invention.

In the sub-claims reference is made, as far as generalizing terms are used, to the terminology as usual in the branch supported by physical data and the technologies as usual to this extent as standardized.

What is particularly to be highlighted is that with the abrasive in accordance with the invention an abrasive composite whose elastically compliant matrix comprises a noncellular thermosetting binder is now applied to a flexibly configured backing in forming an integral composite directly, i.e. without the promotion of a separate bonding layer, whereby in consumption of the abrasive the grains continually worn out are replaced from the depth of the matrix, this applying continued until total or near total wear out of the abrasive composites down to the flexible backing without loss of abrasion quality. In this arrangement the elastically compliant configuration in the abrasive composites comprising matrix and abrasive grains can endow the complete abrasive in conjunction with the flexibility of the backing a native flexibility which can be tailored to the particular application. In addition to this, it is now possible to make available to the customer the same abrasive, irrespective of this at his end needing to be flexible or not in abrading in thus no longer making it necessary in many applications to stock a wealth of different abrasives for such applications having differing requirements on the flexibility of the abrasive.

Claims 2 and 3 relate to preferred upper and lower limits for the density of the binder in the matrix and abrasive composite respectively.

Claims 4 to 8 relate to preferred selection criteria as regards the elastically compliable configuration of the matrix with reference to elasticity (claims 4 and 5), hardness (claims 6 and 7) and ultimate elongation (claim 8).

The limiting values cited in the claims 2 to 8 for the ranges of density (claims 2 and 3), elasticity (claims 4 and 5), hardness (claims 6 and 7) and ultimate elongation (claim 8) are established standardized, particularly on the basis of German DIN standards or the worldwide valid ISO standards, each relating to the other as follows:

density: DIN 53479 and ISO 1183 (claims 2 and 3) respectively

elasticity: DIN 53513 and ISO 527-2 (claims 4 and 5) respectively

hardness: DIN 53505 and ISO 868 (claims 6 and 7) respectively

ultimate elongation: DIN 53504 and ISO 527-1 (claim 8) respectively.

Claim 9 recites preferred criteria under which the backing of the matrix or of the abrasive composite is claimed to be flexible.

Claims 10 and 11 relate to preferred dimensions for the thickness of the matrix perpendicular to the backing as claimed minimally (claim 10) and maximally (claim 11). Currently, the thicknesses as preferred for application are 1000 μm, i.e. 1.0 mm and 1500 μm, i.e. 1.5 mm. One application of the invention particularly highlighted is in this sense the fabrication of the abrasive as flat material, especially as web material.

Claims 12 and 13 relate to preferred dimensions for the ratio of the percentage by volume of the abrasive grains and of the binder of the matrix in claiming a lower limit (claim 12) and an upper limit (claim 13).

Claim 14 recites preferred grain size ranges of the abrasive grains.

Claim 15 recites preferred ranges for the Shore hardness of the abrasive.

Claims 16 to 20 relate to preferred materials for the non-cellular thermosetting binder which as claimed in claim 21 may be filled as usual in the branch whilst claims 22 and 23 recite special formulations.

Claim 24 relates to a special formulation for the case of the binder being foamable which in the scope of the invention is to be avoided as best possible. For this purpose claim 24 recites use especially of a foam inhibitor as an additive to the binder.

Claims 25 and 27 relate to preferred selections as to the type of abrasive grains.

Claims 28 to 30 relate to preferred arrays of the abrasive grains in the matrix.

Claims 31 to 34 relate to preferred sub-divisionings of the matrix into individual matrix bodies.

Claims 35 to 38 relate to preferred configurations of the backing.

Claims 39 to 42 relate to preferred geometric configurations of the abrasive for various abrasive tools.

Claim 43 in conclusion relates to a preferred configuration of the original contact surface of the abrasive in its configuration as marketed prior to its use on the abrasive tool.

Of particularly interest is the variant as recited in claim 39 in which the abrasive in accordance with the invention is configured as an endless belt, in this configuration its effect on the workpiece for the same abrasive can also be varied according to the location of the endless belt resulting in the effect on the workpiece. The locations particularly preferably for the effect are, on the one hand, on a contact wheel and, on the other, on a free side of the endless belt whereby also the hardness of the contact wheel and the belt speed may serve as influencing factors.

The invention relates also to methods of fabricating the abrasive in accordance with the invention as claimed in claims 44 to 49.

One method known as such reads from U.S. Pat. No. 5,562,745.

The invention will now be detailed by way of a special example embodiment with reference to the FIGS. 1 to 3 illustrating the gist of the invention in general.

FIG. 1 shows the contact surface of the abrasive in a partial view whilst

FIG. 2 is a partial view on a magnified scale of that as shown in FIG. 1 corresponding to the white circle therein and

FIG. 3 is an illustration of a cross-section portion of the same abrasive perpendicular to the contact surface on a further magnified scale.

In the abrasive as shown in all of the FIGs. a flexible supporting backing 2 is bonded to a matrix 4 (shown dotted in FIG. 3) comprising an elastically compliant and non-cellular thermosetting binder 6 e.g. of unfoamed polyurethane together with fillers and additives, whereby abrasive grains 8 are embedded in the matrix 4 homogenously dispersed or in layers parallel to the backing 2. In this arrangement the binder 6 serves not only to bind the abrasive grains 8 in the matrix 4 but also the matrix 4 to the backing 2 in thus doing away with the need of a separate bonding layer between matrix 4 and backing 2.

Configured on the side of the matrix 4 facing away from the backing 2 is a free contact surface 10 parallel to the backing 2. When the abrasive is not in use free scabs of the abrasive grains 8 slightly protrude from the contact surface 10 (not shown) subject to the return force of the elastically compliant binder 6. When in use, the abrasive grains in the region of the contact surface 10 interact with a workpiece (not shown) against the return force of the elastically compliant binder 6 in becoming fully, or near fully impressed into the matrix 4. However, in its original condition or prior to use of the abrasive the abrasive grains 8 jut from the contact surface only sufficiently to form a microstructure together with the binder 6 of the matrix 4 at the contact surface 10.

In addition, the special embodiment as illustrated features the following special aspect:

In a full-length backing 2 the matrix 4 is divided into a plurality of the regular hexagonal matrix bodies 4 a whose defining surfaces at the hexagonal profile are oriented perpendicular to the backing 2 so that no matter how worn the matrix 4 becomes the same regular hexagonal cross-section of each matrix body 4 a to each backing 2 or parallel to the contact surface 10 remains.

Each single matrix body 4 a juts from the backing 2 with a full-length interspace 12 dimensioned consistently inbetween and extending from the backing 2 to the region of the contact surface 10.

The interspaces 12 can be used for air or liquid cooling of the workpiece (not shown).

As shown, the matrix bodies 4 a form a homogenously honeycomb structure of the matrix 4. In this arrangement the abrasion direction 16 is selected so that it is oriented along the imaginary line connecting the two opposing corners of a matrix body 4 a, these in turn being arranged mutually staggered in forming a gap so that even when a matrix body 4 a is destabilized mutual support by a neighboring non-destabilized matrix body 4 a is assured.

Irrespective of the special hexagonal configuration of the individual matrix bodies 4 a as shown in this case, their configuration and array in the matrix 4 are selected so that the connection of the matrix 4 resolved into individual matrix bodies 4 a with the backing 2 enhances the flexibility of the abrasive composite as a whole. This is particularly and especially of advantage when the abrasive is an endless belt (not shown).

Test Example:

Test Parameters:

tubestock belt grinder: Flex LBR 1506 VRA, 1200 Watt

Belt length (endless belt): 40 mm×618 mm

Cutting speed: 14 m/s

Workpiece: stainless steel tubestock, material No. 1.4301,

dimension: 50 mm.×2.5 mm

handling: machine guided by hand over tubestock

Test Preparation:

The stainless steel tubestock is firstly rough ground on a centerless abrasive machine with an abrasive belt grain size P 80. The average peak-to-valley height after the rough cut is approx Ra=2.6 μm.

Test Implementation:

For stainless steel railings or frontings an average peak-to-valley height of Ra=0.5 μm is normally specified. This is usually achieved by using the following grain sequence: P120-P180-P280. The abrasive belts employed are e.g. standard abrasive belts CS 310 XF (flexible cotton backing approx. 320 g/m², abrasive grain aluminum oxide, phenolic resin binder). To achieve the specified finish at least three runs with the machine (grain P120-P180-P280) were needed.

For comparison an endless belt in accordance with the invention was used in the same test configuration and with same test preparation, the characteristics of the belt being as follows: flexible cotton backing approx. 320 g/m², polyurethane as non-cellular thermosetting binder with a layer thickness of 1200 μm, abrasive grain silicon carbide P60 homogenously dispersed in the binder.

The average peak-to-valley height of Ra=0.5 μm was achieved in just a single run. 

1. An abrasive wherein abrasive grains are embedded in a matrix comprising a non-cellular, particularly non-foamed thermosetting binder for the abrasive grains, and wherein a contact surface covered by abrasive grains is configured for abrasion of a workpiece, characterized by the combination of the following features: a) the matrix is elastically compliant to such an extent that the abrasive grains covering the contact surface are impressed into the matrix during abrasion; b) the abrasive grains are dispersed in the matrix such that the consumption of the matrix perpendicular to the contact surface covered originally with abrasive grains releases a further contact surface covered with abrasive grains; c) the abrasive grains are dispersed in the matrix such that they comply with the return force of the matrix both perpendicular and parallel to the corresponding contact surface of the abrasive; d) the matrix is bonded to a flexible backing; e) bonding the matrix to its flexible backing is achieved directly via the binder contained in the matrix.
 2. The abrasive as set forth in claim 1, characterized in that a binder is termed non-cellular when the density of the binder in the matrix is not lower than 70% of the specific density of the substance of the binder.
 3. The abrasive as set forth in claim 1, characterized in that a binder is termed non-cellular when the density of the binder in the matrix is not lower than 85%, preferably 90% of the specific density of the substance of the matrix.
 4. The abrasive as set forth in claim 1, characterized in that the binder is termed elastically compliant when the elasticity of the matrix is not less than 35%, preferably 40%.
 5. The abrasive as set forth in claim 1, characterized in that the binder is termed elastically compliant when the elasticity of the matrix is not higher than 55%, preferably 50%.
 6. The abrasive as set forth in claim 1, characterized in that the binder is termed elastically compliant when the hardness of the matrix is not lower than 40 Shore A, preferably 45 Shore A.
 7. The abrasive as set forth in claim 1, characterized in that the binder is termed elastically compliant when the hardness of the matrix is not higher than 75 Shore A, preferably 70 Shore A.
 8. The abrasive as set forth in claim 1, characterized in that the binder is termed elastically compliant when the ultimate elongation of the matrix is not lower than 150%, preferably 170%.
 9. The abrasive as set forth in claim 1, characterized in that the backing is termed elastically compliant when the flexural rigidity of the backing over a sensing width of 15 mm, with a sensing spacing of 20 mm and an angle of rotation of 15° is not higher than 5000 mN
 10. The abrasive as set forth in claim 1, characterized in that the thickness of the matrix perpendicular to the backing is not lower than 200 μm, preferably not lower than 500 μm, most preferably not lower than 1000 μm.
 11. The abrasive as set forth in claim 1, characterized in that the thickness of the matrix perpendicular to the backing is not higher than 2500 μm, preferably not higher than 1500 μm.
 12. The abrasive as set forth in claim 1, characterized in that in the ratio of the volume percentage of the abrasive grains to that of the binder of the matrix the volume percentage of the abrasive grains is smaller or maximally equals 80 volume %, preferably smaller than or maximally equals 60 volume %.
 13. The abrasive as set forth in claim 1, characterized in that in the ratio of the volume percentage of the abrasive grains to that of the binder of the matrix the volume percentage of the abrasive grains is greater than or minimally equals 20 volume %, preferably greater than or minimally equals 40 volume %.
 14. The abrasive as set forth in claim 1, characterized in that the abrasive grains range in size from 2 μm to 2000 μm preferably 70 μm to 540 μm, most preferably have size P36, P60, P120 and P240 as per the FEPA standard.
 15. The abrasive as set forth in claim 1, characterized in that the Shore hardness of the abrasive in the Shore hardness A range is preferably between 60° and 90° Shore A.
 16. The abrasive as set forth in claim 1, characterized in that the binder comprises a polyurethane, preferably is made of one such polyurethane.
 17. The abrasive as set forth in claim 1, characterized in that the binder comprises a rubber, preferably is made of one such rubber.
 18. The abrasive as set forth in claim 1, characterized in that the binder comprises a polysulfide, preferably is made of one such polysulfide.
 19. The abrasive as set forth in claim 1, characterized in that the binder comprises a polysulfide, preferably is made of one such polysulfide.
 20. The abrasive as set forth in claim 1, characterized in that the binder comprises an acrylate, preferably is made of one such acrylate.
 21. The abrasive as set forth in claim 1, characterized in that the binder is filled.
 22. The abrasive as set forth in claim 1, characterized in that the matrix contains in addition to the binder at least one filler and/or at least one dyestuff and/or at least one other additive.
 23. The abrasive as set forth in claim 21, characterized in that kaoline is provided as the filler.
 24. The abrasive as set forth in claim 22, characterized in that at least one foam inhibitor is provided as an additive.
 25. The abrasive as set forth in claim 1, characterized in that the abrasive grains comprise at least one silicon carbide and/or at least one silicon oxide, preferably consists thereof.
 26. The abrasive as set forth in claim 1, characterized in that the abrasive grains consist of at least one aluminum oxide and/or at least one aluminum oxide mixed crystal.
 27. The abrasive as set forth in claim 1, characterized in that at least a portion of the abrasive grains consists of at least one hardmetal.
 28. The abrasive as set forth in claim 1, characterized in that the abrasive grains in their array nearest to the backing rest on the backing.
 29. The abrasive as set forth in claim 1, characterized in that the abrasive grains are homogenously dispersed in the matrix.
 30. The abrasive as set forth in claim 1, characterized in that the abrasive grains are arranged in the matrix in several layers over the backing.
 31. The abrasive as set forth in claim 1, characterized in that the matrix including its abrasive grains is divided into several matrix bodies dispersed over the same backing with mutual spacing, the matrix bodies having a consistent cross-section preferably in the direction perpendicular to the originally contact surface or backing.
 32. The abrasive as set forth in claim 31, characterized in that the matrix bodies have a polygonal cross-section parallel to the backing and are preferably arranged mutually staggered in the abrasion direction.
 33. The abrasive as set forth in claim 32, characterized in that the polygonal cross-section is hexagonal and preferably oriented with two comers in or opposing the abrasion direction.
 34. The abrasive as set forth in claim 31, characterized in that the matrix bodies a have a circular cross-section parallel to the backing and are arranged mutually staggered preferably in the abrasion direction.
 35. The abrasive as set forth in claim 1, characterized in that the backing consists of a woven, knitted fabric, film, filament layer and/or one or more non-regulated layers of fibers such as paper, fiber or a non-woven.
 36. The abrasive as set forth in claim 35, characterized in that the backing consists of natural or man-made fibers and/or mixtures thereof.
 37. The abrasive as set forth in claim 1, characterized in that the backing is inherently elastically compliant.
 38. The abrasive as set forth in claim 1, characterized in that the backing has a quality finish.
 39. The abrasive as set forth in claim 1, characterized by a configuration as an endless belt.
 40. The abrasive as set forth in claim 1, characterized by a configuration as flat material, preferably strips for oscillating drive.
 41. The abrasive as set forth in claim 1, characterized by a configuration as disk or bow for oscillating drive.
 42. The abrasive as set forth in claim 1, characterized by a configuration as a disk, segmented abrasive disk, laminated abrasive point or wheel for rotational drive.
 43. The abrasive as set forth in claim 1, characterized in that the originally contact surface is patterned at the most in the micro-range.
 44. A method of fabricating an abrasive as set forth in claim 1, characterized in that the abrasive grains are firstly admixed in the matrix with a binder still at low viscosity before this mixture is applied to the backing.
 45. The method of fabricating an abrasive as set forth in claim 1, characterized in that firstly the binder whilst still of low viscosity is applied to the matrix on the backing and then the abrasive grains so that the abrasive grains sink into the backing whilst the binder is still at a low viscosity.
 46. The method as set forth in claim 45, characterized in that the abrasive grains are dispersed on the matrix whilst the binder is still at a low viscosity.
 47. The method as set forth in claim 45, characterized in that the abrasive grains are applied to the matrix applied in all prior to the backing in several passes whilst the binder is still at a low viscosity.
 48. The method as set forth in claim 44, characterized in that the matrix containing the binder and the abrasive grains are applied to the backing together or separately in a multi-coating process.
 49. The method of fabricating an abrasive as set forth in claim 31, particularly as set forth in claim 44, characterized in that a masking technique is used when configuring the matrix bodies arranged with mutual spacing on the backing. 